1. Field of the Invention
The present invention relates to an exhaust muffler and to a muffler system for connecting to an exhaust pipe of an internal combustion engine, used on a motorcycle or four-wheeled vehicle. More particularly, the present invention relates to an exhaust muffler and related muffler system, for connecting to an exhaust pipe of an internal combustion engine used on a motorcycle or four-wheeled vehicle, in which an exhaust muffler is convertible between a first configuration, for use on public roads where low noise is required, and a second configuration for use in racing competition, where enhanced performance is required.
2. Description of the Background Art
Vehicular exhaust mufflers have been known that define a plurality of expansion chambers using a plurality of bulkheads, and that are provided with a removable spark arrester equipped with a tail pipe at a rear part thereof.
A spark arrester is a device for catching and trapping sparks and soot included in exhaust gas of an internal combustion engine, and for preventing the sparks and soot from being released to the atmosphere. When the spark arrester is detachable, exhaust back pressure in the expansion chambers is usually set to be highest at the expansion chamber closest to the front near the exhaust pipe, and becomes sequentially lower as it moves rearwardly within the exhaust muffler. The object of providing a detachable spark arrester is to enable maintenance of the muffler and the spark arrester, and to enable changing of the spark arrester in order to economically provide exhaust devices for differing performance requirements.
An exhaust muffler including a removable and replaceable spark arrester is described in Japanese Patent Laid-open Publication No. Hei. 10-266828 (refer, for example, to effects of the invention, FIG. 2, and FIG. 5 of the reference).
Although the known devices have some utility for their intended purposes, a need still exists in the art for an improved exhaust muffler for an internal combustion engine. In particular, there is a need for an improved exhaust muffler for an internal combustion engine.